Liver disease can be broadly classified into hepatocellular injury and cholestatic disease that results from biliary disease or obstruction. The following tests are typically performed in labs as a test of liver health.

The most common causes for elevation in liver enzymes are listed as follows. Medications can cause both hepatocellular and cholestatic injury. Many medications can cause mild to modest hepatitis but only a few cause frank liver failure. A notable example is acetaminophen at high doses.

Other less common disease processes causing liver dysfunction include hemochromatosis (disorder of iron storage), Wilson disease (impaired cellular copper transport), autoimmune disease, alpha-1-antitrypsin deficiency (extra-pulmonary manifestation), and thyroid disorders. Some causes of biliary disease are Gilbert syndrome, hemolytic anemias , primary biliary cirrhosis, primary sclerosing chlolangitis, and other causes of bile duct obstruction.

Psychotropic medications usually act by injury to hepatic cells though a cholestatic mechanism is implicated with some medications. The mechanism is metabolic or immune mediated. Some medications cause liver abnormalities by causing weight gain and subsequent fatty liver disease . Two psychotropic medications commonly known to cause liver injury are valproate (microvesicular steatosis is seen in liver cells) and carbamazepine (the liver toxicity appears to be part of a systemic hypersensitivity syndrome).

Generally, the liver enzymes (usually transaminases ) rise in the first 3–6 months of treatment. Mild hepatitis is seen in up to 30% patients on antipsychotics [1, 2]. Clinically significant elevations that require the medication to be discontinued occur in less than 5% cases. The prevalence of transaminase elevation with antidepressants, including clinically significant elevations, is less than 3% [3].

Naltrexone is generally safe to use in patients with preexisting liver disease. Though some studies suggest rise in transaminases up to 50%, clinically significant elevation occurs only in 1% patients [4].

Clinically significant elevation is considered rise of transaminases to at least more than two times normal or presence of clinical symptoms. Liver enzymes generally return to normal when the medication is stopped. Even when medication is continued, the enzyme abnormality has been reported to resolve in approximately 50% cases of antipsychotics [1]. Age and polypharmacy are risk factors to develop hepatic injury. Preexisting liver disease may predispose to developing hepatitis though evidence is unclear on this. Liver injury is generally considered to be independent of medication dose .